Fuel injection pumps



June 11, 1963 G. R. NORTH 3,693,125

FUEL INJECTION PUMPS Filed 001. 20. 1960 2 Sheets-Shet 1 INVENTO/L WWW WM,MM iz/4m 4rramE/I June 11, 1963 G. R. NORTH 3,093,125

FUEL INJECTION PUMPS Filed 001:. 20. 1960 2 Sheets-Sheet 2 WI/M United States Patent 3,093,125 FUEL INIECTION PUMPS Geoffrey Robson North, London, England, assignor to Simms Motor Units Limited, London, England, a Eritish company Filed Oct. 20, 1960, Ser. No. 63,359 Claims. (Cl. 123140) The invention relates to fuel injection pumps for supplying fuel to the combustion chambers of internal combustion engines e.g. diesel engines.

The invention provides a device for controlling a fuel injection pump for supplying fuel to an internal com bustion engine, which device comprises a control rod which is movable longitudinally (eg by a governor) to control the rate of supply of fuel by the pump, a first control member rotatable about an axis to move the control rod longitudinally, an abutment carried by the control rod for movement therewith, a second control member movable along the said axis between a normal limiting position, in which it lies in the path of the abutment to prevent the rate of supply of fuel exceeding a normal maximum rate, and an excess fuel position, in which it permits the abutment to be carried past the said second control member by the control rod to permit an excess rate of fuel supply for starting the engine, a pawl carried by the abutment or the control rod and biassed transversely of the direction of movement of the control rod and abutment to a limiting position in which it co-operates with the second control member, when it is in its excess fuel position, to prevent the rate of fuel supply from exceeding a predetermined value (which is preferably equal to or less than the normal maximum rate), the arrangement being such that in moving from its normal limiting position to its excess fuel position when the engine is to be started the second control member moves the pawl against its bias and away from its limiting position, thereby to permit the said excess rate of fuel supply, the pawl moving under its bias to its limiting position when the control rod subsequently moves to reducethe rate of fuel supply to a value equal to or less than the said predetermined value.

A specific construction of apparatus embodying the invention will now be described by way of example and with reference to the accompanying drawings in which:

FIGURE 1 is a longitudinal sectional View,

FIGURE 2 is a part-sectional view on the line 2-2 of FIGURE 1,

FIGURE 3 is a part-sectional view on the line 33 of FIGURE 2,

FIGURE 4 is a part sectional view similar to FIG- URE 3 showing the apparatus in an excess fuel position, and

FIGURE 5 is a section with some parts omitted on the line 55 of FIGURE 2.

In this example the apparatus controls a fuel injection pump of the type known commercially as Simms type SPE-M or type SPE-A or type PA or type SPE-B, or as described in British patent specification No. 827,678. In these pumps the effective pumping strokes of the plungers, and consequently the rate of supply of fuel by the pump, is controlled by means of a control rod 11 which is either (a) in toothed engagement with gear segments either on the sleeves in which the plungers reciprocate, or on the plungers, or (b) carries forks engaging with radial arms on those sleeves or plungers, so as to cause relative rotation between the plungers and sleeves when the control rod is moved longitudinally. A helical port on the plunger cooperates with a spill port in the sleeve so that the length of each injection period is determined by the angular relationship of the plunger relative to the sleeve.

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One end of the control rod .11 is connected by means of a coupling piece 12 to a pneumatic governor 13 which is a modified form of the type known commercially as Simms type GP. The coupling piece 12 is secured to the control rod 11 by means of a grub screw 44 and has a channel portion 45 which cooperates with a guide rod 46.

The pneumatic governor 13 comprises a chamber 14 which is closed at one end by a flexible diaphragm 15 and has an air inlet 16 and an outlet 17 which are connected respectively to the air intake of the engine, in the region of the throttle valve, the air inlet 16 communicating with the chamber 14 by way of a damping valve 18. The diaphragm 15 is biassed to the left (as viewed in FIGURE 1) by a compression spring 19, so that when the engine is stationary the spring 19 positions the control rod '11 so that the pump is set for supplying fuel at the normal maximum rate.

That normal maximum rate is determined by a control member in the form of a maximum fuel stop lever 21 carried by a shaft 24 and having two arms 22, 23. The arm 22 abuts against a stop 25 which is screwthreaded through the casing at 26 and is provided with a locking nut 27 so that the position of the stop 25 may be adjusted to determine the value of the normal maximum rate. The arm 23 of the lever 21 is engaged by a member 28 which secures the coupling piece 12 to a rod 29 which is in turn secured to the diaphragm 15 of the governor 13. The member 28, the rod 29 and the nut 29a are formed integrally and are secured to the diaphragm '15 by screwing the nut 29w onto the threaded rod which passes through the centre of the diaphragm 15. A yoke, of which the part 43 forms one arm, fits around the rod 29 between the member 28 and the nut 29a.

The shaft 24 passes through a short hollow shaft 31 which carries another control member (the engine stop lever) 32 for limited rotational movement about an axis of the shaft 24. The hollow shaft 31 has secured to it a lever 35 so that the engine stop lever 32 may be rotated in the anti-clockwise direction (as viewed in FIGURE 1) to abut against the coupling piece 12 to move the control rod 11 to the right (as viewed in FIGURE 1) for the purpose of stopping the engine. When the control rod 11 is moved to its limit position to the right it cuts off supply of fuel to the pump.

The shaft 24 carrying the maximum fuel stop lever 21 is biassed to the left (as viewed in FIGURE 2) by a compression spring 36, and the end 37 of the shaft 24 projects to form a push button. When that push button is pressed it moves the shaft 24 against the action of the spring 36 and carries the maximum fuel stop lever 21 to an excess fuel position which is shown in broken lines at 21a. The coupling piece 12 has pivoted to it at 38 a pawl 39 having an arm 39w fixed at 3% to a rod which forms the pivot at 38, and a lateral projecting head 41. One end of a spring 42 is clamped at 42a (see FIGURE 5) to the rod to which is attached arm 39a of the pawl 39, and the other end 4211 of the spring 42 (see FIGURE 2) projects into a hole in the coupling member 12. The pawl 39 is biassed by the spring 42 to a position in which the head 41 abuts against the part 43 of the coupling member 12, as shown in FIG- URE 2. When the maximum fuel stop lever 21 moves from its normal limiting position to its excess fuel position 21a it moves the pawl 39 against its bias (as shown in FIGURE 4), so that when the maximum fuel stop lever reaches its excess fuel position it lies out of the path of movement of the coupling member 12, and the control rod 11 is thus moved further to the left (as viewed in FIGURE 1) by the spring 19 and the pump can then supply fuel at a rate in excess of the normal maximum rate, for the purpose of starting the engine.

As soon as the engine starts, the pneumatic governor 13 then exerting minimum vacuum with lowest engine speed, pulls the control rod to the right (as viewed in FIGURE 1), and then the pawl 39 is carried beyond the maximum fuel stop lever 23 the pawl 39 is returned by its spring 42 back into its limiting position, as shown in FIGURE 2. With increase in engine speed the vacuum of the pneumatic governor decreases and the spring 19 then tends to push the control rod 11 to the left (as viewed in FIGURE 1). Consequently, if the push button 37 is maintained in its pressed position, or is pressed while the engine is running, the maximum rate of supply of fuel by the pump is determined by abutment of the pawl 39 against the arm 23 of the maximum fuel stop lever and, owing to the thickness of the pawl 39, that maximum rate is less than the normal maximum rate.

The apparatus thus permits temporarily an excess rate of fuel delivery by the pump to the engine when the engine is started, but ensures that the excess rate of fuel supply cannot be maintained or obtained once the engine has started.

The invention is not restricted to the details of the foregoing example.

I claim:

1. A control device comprising, in combination, a control rod movable longitudinally in both directions, a first control member rotatable about an axis to move the control rod longitudinally, an abutment member carried by the control rod for movement therewith, a pawl movable with the said abutment member, means biassing the pawl towards a position adjacent the abutment member, a second control member normally in the path of the abutment member, whereby longitudinal movement in one direction of the control rod is limited by abutment of the abutment member against the said second control member, the said second control member being movable along the said axis to a position in which it is in the path of the pawl when the pawl is adjacent the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the pawl against the second control memher the pawl being at least as near as the abutment member to the second control member, in the longitudinal direction of the control rod, the pawl being moved against its bias away from its position adjacent the abutment member when the second control member is moved from abutment with the abutment member along the axis as aforesaid, whereby movement in the said one direction of the pawl and the abutment member past the said second control member is permitted temporarily.

2. A control device as claimed in claim 1, in which the said second control member is pivoted on the said axis and has two arms, one of the said arms being normally in the path of the abutment member and the other of the said arms abutting against an adjustable stop, whereby the position of the said one arm relative to the abutment member is adjustable.

3. A control device comprising, in combination, a control rod movable longitudinally in both directions, a governor chamber for containing fluid, a pressure responsive member responsive to pressure of fluid in the governor chamber, the said control rod being connected to the pressure responsive member for longitudinal movement thereby, a first control member rotatable about an axis to move the control rod longitudinally, an abutment member carried by the control rod for movement therewith, a pawl movable with the said abutment member, means biassing the pawl towards a position adjacent the abutment member, a second control member normally in the path of the abutment member, whereby longitudinal movement in one direction of the control rod is limited by abutment of the abutment member against the said second control member, the said second control member being movable along the said axis to a position in which it is in the path of the pawl when the pawl is adjacent the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the pawl against the second control member the pawl being at least as near as the abutment member to the second control member, in the longitudinal direction of the control rod, the pawl being moved against its bias away from its position adjacent the abutment member when the second control member is moved from abutment with the abutment member along the axis as aforesaid, whereby movement in the said one direction of the pawl and the abutment member past the said second control member is permitted temporarily, and a single casing forming a continuation of the governor chamber, which casing contains the control members, the abutment member, the pawl, the biassing means, and part of the control rod, the control rod projecting through the casing.

4. In combination with an internal-combustion engine, a governor for controlling the speed thereof and a fuel injection pump for supplying fuel to the engine, a control device comprising, a control rod movable longitudinally in both directions to control the rate of supply of fuel to the engine, which control rod is moved under control of the governor to move in one direction to increase the rate of fuel supply and in the other direction to decrease it, a first control member rotatable about an axis to move the control rod longitudinally in the said other direction to cut off the fuel supply to stop the engine, an abutment member carried by the control rod for movement therewith, a pawl movable with the said abutment member, means biasing the pawl towards a position adjacent the abutment member, a second control member normally in the path of the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the abutment member against the said second control member thereby to limit the rate of fuel supply to a normal maximum rate, the said second control member being movable along the said axis to a position in which it is in the path of the pawl when the pawl is adjacent the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the pawl against the second control member the pawl being at least as near as the abutment member to the second control member, in the longitudinal direction of the control rod, whereby when the pawl abuts against the second control member the maximum rate of fuel supply is not greater than the said normal maximum rate, the pawl being moved against its bias away from its position adjacent [the abutment member when the second control member is moved from abutment with the abutment member along the axis as aforesaid, whereby movement in the said one direction of the pawl and the abutment member past the said second control member is permitted temporarily thereby to permit temporarily an excess rate of fuel supply in starting the engine.

5. In combination with an internal combustion engine, a governor for controlling the speed thereof, which governor includes a governor chamber for containing fluid and a pressure responsive member responsive to pressure of fiuid in the governor chamber, and a fuel injection pump for supplying fuel to the engine, a control device comprising, a control rod movable longitudinally in both directions to control the rate of supply of fuel to the engine, the said control rod being connected to the said pressure responsive member to move in one direction to increase the rate of fuel supply and in the other direction to decrease it, a first control member rotatable about an arms to move the control rod longitudinally in the said other direction to cut off the fuel supply to stop the engine, an abutment member carried by the control rod for movement therewith, a pawl movable with the said abutment member, means biasing the pawl towards a position adjacent the abutment member, a second control member normally in the path of the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the abutment member against the said second control member thereby to limit the rate of fuel supply to a normal maximum rate, the said second control member being movable along the said axis to a position in which it is in the path of the pawl when the pawl is adjacent the abutment member, whereby longitudinal movement in the said one direction of the control rod is limited by abutment of the pawl against the second control member the pawl being at least as near as the abutment member to the second control member, in the longitudinal direction of the control rod, whereby when the pawl abuts against the second control member the maximum rate of fuel supply is not greater than (the said normal maximum rate, the pawl being moved against its bias away from its position adjacent the abutment member when the second control member is 6 moved from abutment with the abutment member along the axis as aforesaid, whereby movement in the said one direction of the pawl and the abutment member past the said second control member is permitted temporarily thereby to permit temporarily an excess rate of fuel supply in starting the engine, and a single casing forming a continuation of the governor chamber, which casing contains the control members, the abutment member the pawl, the biasing means, and part of the control rod, the

10 control rod projecting through the casing.

References Cited in the file of this patent UNITED STATES PATENTS 15 2,588,560 Nicolls Mar. L1, 1952 2,716,901 Howe Sept. 6, 1955 2,905,020 Ziesche et a1 Sept. 22, 1959 

1. A CONTROL DEVICE COMPRISING, IN COMBINATION, A CONTROL ROD MOVABLE LONGITUDINALLY IN BOTH DIRECTIONS, A FIRST CONTROL MEMBER ROTATABLE ABOUT AN AXIS TO MOVE THE CONTROL ROD LONGITUDINALLY, AN ABUTMENT MEMBER CARRIED BY THE CONTROL ROD FOR MOVEMENT THEREWITH, A PAWL MOVABLE WITH THE SAID ABUTMENT MEMBER, MEANS BIASSING THE PAWL TOWARDS A POSITION ADJACENT THE ABUTMENT MEMBER, A SECOND CONTROL MEMBER NORMALLY IN THE PATH OF THE ABUTMENT MEMBER, WHEREBY LONGITUDINAL MOVEMENT IN ONE DIRECTION OF THE CONTROL ROD IS LIMITED BY ABUTMENT OF THE ABUTMENT MEMBER AGAINST THE SAID SECOND CONTROL MEMBER, THE SAID SECOND CONTROL MEMBER BEING MOVABLE ALONG THE SAID AXIS TO A POSITION IN WHICH IT IS IN THE PATH OF THE PAWL WHEN THE PAWL IS ADJACENT THE ABUTMENT MEMBER, WHEREBY LONGITUDINAL MOVEMENT IN THE SAID ONE DIRECTION OF THE CONTROL ROD IS LIMITED BY ABUTMENT OF THE PAWL AGAINST THE SECOND CONTROL MEMBER THE PAWL BEING AT LEAST AS NEAR AS THE ABUTMENT MEMBER TO THE SECOND CONTROL MEMBER, IN THE LONGITUDINAL DIRECTION OF THE CONTROL ROD, THE PAWL BEING MOVED AGAINST ITS BIAS AWAY FROM ITS POSITION ADJACENT THE ABUTMENT MEMBER WHEN THE SECOND CONTROL MEMBER IS MOVED FROM ABUTMENT WITH THE ABUTMENT MEMBER ALONG THE AXIS AS AFORESAID, WHEREBY MOVEMENT IN THE SAID ONE DIRECTION OF THE PAWL AND THE ABUTMENT MEMBER PAST THE SAID SECOND CONTROL MEMBER IS PERMITTED TEMPORARILY. 